the secrets behind truss bridges

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Transcript of the secrets behind truss bridges

Truss Bridges Hisory! Bowstring Bailey K Truss Howe Pratt Warren deck truss through truss William Howe designed the Howe truss bridge in 1840 ths is one of Howe's bridge's The Bailey is used by the military,it cover gaps of about 60 m. The bridge can bear the weight of tanks and doesn't require any kind of heavy machinery or tools for construction. In the K Truss,the design of this bridge is complicated and is considered to be one of the hardest bridges to build. The Bowstring arch truss bridge, which is also known as Tied arch bridge, The vertical load faced by thrust arches in this bridge is transferred along the path of the arc The Pratt had longer diagonal members are in tension. This allows the shorter vertical pieces to be in compression. However, it was used later in steel bridges. It's impressive strength over long spans contributed to its overwhelming popularity as a railroad bridge. The Howe, it was originally designed to combine diagonal timber compression members and vertical iron rod tension members The warren:It has equilateral triangles to spread out the loads on the bridge; the equilateral triangles minimize the forces to only compression and tension. This happens especially to the members near the center of the bridge. By Samantha Bolduc Between the 1500'sand 1700's builders around the world used timber for building material In 1500's the main style for bridges were the basic kingpost and queenpost designs <- Kingpost bridge Queenpost bridge -> 2. 3. 4. 5. Europe invented a few woodentruss bridges until the 18thcentury and then and insteadswitched to steel/metal trussbridges along with the U.S. 8. 1. Why might truss bridges have roofs on top of them?they were intended to protect the bridge from bad weather and it helped to make the bridge last three times longer! 6. In the mid 1700's, the U.S. had very limited transportation because the Revolutionary War needed all the wood, steel, and metal they could get. 7. When the war ended, builders quickly gained materials again to start building wooden truss bridges 9. Lastly,In 1844, Caleb Pratt invented the pratt truss bridge 10. Bibliography

http://www.past-inc.org/historic-Bridges/metaltruss.html

http://pacoveredbridges.com/history-design.html

http://www.tdot.state.tn.us/bridges/historybridges.htm This bridge was designed to put together timber compression. Joseph B. Strauss Built the golden gate bridge 4 After reading about the Warren truss and learning how sturdy and strong the Warren truss is, we decided to build one. it was built because there was no other way to get across the bay besides fariy it costed 30 million dollors he choose it because its strong structure. james warren this bridge is built with triangles to spread out the weight of the loads By:Caitlyn 2 We did the Warren truss because it's the simpliest yet strongest bridge design. One of the things that makes the Warren truss different is it uses equilateral triangles. Equilateral triangles help spread out the weight of the load. The equilateral triangles minimize the forces to only compression and tension.This made an improvement over the old Neville truss. 1 Our group did the warren truss. 3 The Warren truss is often part of the structure professional designers use in bridge construction. The Warren truss quickly became a common type of contruction for bridges. Historians say that the Warren truss became common scenery for Americans. http://www.garrettsbridges.com/design/warren-truss/ http://www.wisegeek.com/what-is-a-warren-truss.htm BIBLIOGRAPHY http://www.ehow.com/info_8241582_different-types-truss-bridges.html